"Leslie Chow is madness," says John Goodman's crime boss in assessing Ken Jeong's maniacally cackling and ever-grating character in The Hangover Part III.

But that's hardly a good reason to center a movie on him.

When the franchise's "Wolfpack" come into Chow's orbit, "bad things happen and people get hurt," says Alan (Zach Galifianakis).

Chow's response: "Yes, that's the point. It's funny."

It's not, however. And that's the biggest problem with The Hangover Part III (* 1/2 out of four; rated R; opens Thursday nationwide).

This sequel makes a major tactical error by focusing excessively on the most outlandish — and least comical— character from the previous films. It's more a road movie with action elements than a comedy, and the debauchery of the first two films is missing. Since the guys aren't stuck in Vegas, drunk or drugged, their willingness to go on a wild adventure doesn't ring true. Wrongheaded attempts at humor abound. For starters, there's a decapitated giraffe.

The core characters from the previous films — Alan, Phil (Bradley Cooper) and Stu ( Ed Helms) — are tasked with tracking down Chow, who absconded with $21 million in gold bars that belong to Marshall (Goodman).

If they don't bring him back, Marshall will kill their beleaguered buddy Doug (Justin Bartha), the groom-to-be who was mostly AWOL from the first film. He has almost as little screen time here.

He's the lucky one.

After staging an intervention, the guys are taking Alan to a rehab center called New Horizons. Who knew that there was rehab for childish, thick-headed fools?

But Alan never makes it there. They get sidetracked by Goodman and his goons, who accost them on the highway. Doug is held hostage and the pack is forced to detour to Tijuana to find Chow and his bounty.

As Chow, Jeong sings bad karaoke and keeps killer chickens in his hotel room. What he neglects to do is be funny. The comedy quotient is also missing from his antics involving a parade of hookers, the slaughter of guard dogs and a cocaine-fueled parachute ride where he sings I Believe I Can Fly.

Nothing about this rote exercise feels remotely fresh. It's a re-tread of the 2009 original, sans the inspired lunacy.

It was that inventive insanity that made the first Hangover so much fun. But the players seem like they're going through the motions here. Cooper and Helms spend their time reacting or making wan snide remarks. Galifianakis tries a bit harder, but Alan's strangeness is more distracting than comical. He does, however, get to have a romance with Cassie (Melissa McCarthy), who is essentially the female version of Alan.

References to the previous films pop up frequently, serving both as padding for the thin plot and reminders of how the series has gone wrong.

Much as the studio, actors and comedy-seeking audience would like it to be otherwise, The Hangover was a one-hit wonder.